The present invention relates generally to bar code printing, and more particularly to bar code scanners and printers that can combine 1D with higher dimension bar codes in a specific area, and then detect and utilize those bar codes.
Bar code technology provides an accurate, easy, and inexpensive method of data storage and data entry for computerized information management systems. A properly designed bar code system can offer substantial improvements in productivity, traceability, and materials management, thereby yielding significant cost savings.
Typically, data is extracted from a 1D bar code symbol with an optical scanner that develops a logic signal corresponding to the difference in reflectivity of the printed bars and the underlying media (spaces). The serial data stored in the symbol is retrieved by scanning over the printed bars and spaces with a smooth, continuous motion. This motion can be provided by an operator moving a hand-held wand, by a rotating mirror moving a collimated beam of light, or by an operator or system moving the symbol past a fixed beam of light. The logic signal representing the bars and spaces supplied by the scanner is translated from a serial pulse stream into computer readable data by a decoder.
As the name implies, most bar codes comprise a series of black and light bars printed in accordance with a unique code that contains information across one dimension, so that data may be represented.
Multi-dimensional bar codes are also in use. For example, two-dimensional (2D) bar codes comprise stacked symbology or multi-row code. 2D bar code also refers to matrix code, which is formulated based on the position of black spots within a matrix. Each black element is the same dimension and it is the position of that element that codes the data.
Ordinary 1D bar code is xe2x80x9cvertically redundant,xe2x80x9d meaning that the same information is repeated vertically. The heights of the bars can be truncated without any loss of information. However, the vertical redundancy allows a symbol with printing defects, such as spots, or voids, to still be read and decoded. For such codes, the higher the bar height, the more probability that at least one path along the bar code will be readable.
In contrast, a 2D code stores information along the height as well as the length of the symbol. Most 2D codes use check words to insure accurate reading. 2D code systems are practical where moving beam laser scanners, charge coupled device (CCD) scanners, and other comparable devices are available. 2D codes can also be read with hand held moving beam scanners by sweeping the horizontal beam down the symbol. However, this way of reading such a 2D symbol by sweeping a contact wand across the symbol has the normal criticality aspects of speed of sweep, resolution of the scanner, and symbol/reader distance.
2D codes were initially developed for applications where only a small amount of space was available for an automatic 1D symbol. However, with increased density of information storage with 2D and higher bar codes, the number of applications for such bar codes is multiplying. As an example of the advantages available from using 2D bar encoding, it is possible in the direct mail field to use 2D codes to store the name, address, and demographic information on the direct mail business reply cards. This larger amount of data in the 2D coding avoids the requirement to reference a remote database, thereby saving significant operational time. More specifically, in such direct mail applications, typically there is less than a 2% return from the mailing. If the return card is only coded with a reference number or access code to a remote database, the few returned cards must be checked against a very large database of potentially millions of names. This checking operation can be quite expensive in computer time. However, if all of the important information is printed in the 2D code at the time the mailing label is printed, then there is very little additional cost, and a potential for great savings when the cards are returned, since the time and expense necessary to access the remote database is avoided. Similar savings can occur in field service applications where servicing data may be stored in a 2D symbol on the equipment. The field engineer uses a portable reader to obtain the information, rather than dialing up the home offices remote computer.
From the above, it can be seen that 1D bar codes can be read with inexpensive bar code scanners that use a moving or a fixed beam and are traditionally used in applications such as product packaging. In contrast, 2D bar codes are often read by page scanners that use a CCD or CIS element and have a higher data density than one dimensional bar codes, but may impose limitations based on their size or location.
A significant problem occurs when some of the bar code readers that will be utilized to read a bar code from a particular item are 1D bar code readers, while other bar code readers are 2D or higher dimensional bar code readers, and are designed to extract extensive amounts of information from the 2D bar code to thereby avoid reference to a remote database. In this instance, it is necessary to have one location on the item for the 1D bar code and a second separate location for the 2D bar code. However, this set up is disadvantageous because it requires two bar code printings. More importantly, it is disadvantageous because it requires two separated spaces on the item, i.e., a space for the 1D bar code and a space for the 2D or higher dimensioned bar code. In instances where the spacing on the item is severely limited, this is a major disadvantage. Additionally, these two separate locations for the bar codes inherently require the ability to locate these two separate locations on the item and to read those locations.
Briefly, the present invention comprises a method for printing barcode, comprising the steps of: obtaining a 1D barcode for an area of a medium; obtaining a 2D bar code; combining the 1D and 2D bar codes in the area to overlap at least in part; and printing the combination of the 2D barcode with the 1D barcode in the area of the medium.
In a further aspect of the invention, the 2D bar code obtaining step comprises the step of selecting a 2D barcode for combining with at least a portion of the 1D barcode in the area of the medium based on a reflectance of at least one of a bar of the 1D barcode after the 2D barcode is combined with at least a portion of the 1D barcode bar, and a space of the 1D barcode after the 2D barcode is combined with at least a portion of the 1D barcode space, relative to a threshold reflectance.
In a yet further aspect of the invention, the method includes the steps of: representing a first amount of data by the 1D barcode; and, representing a second amount of data, which second amount is larger than the first amount, by the 2D barcode.
In a further aspect of the present invention, the reflectance in the selecting a 2D barcode step is determined for an addition of the 2D barcode to at least a portion of the bar or space of the 1D barcode.
In a further aspect of the present invention, the reflectance in the selecting a 2D barcode step is determined for the 2D barcode replacing at least a portion of the bar or space of the 1D barcode.
In a yet further aspect of the present invention, the reflectance is a worst case reflectance approximation for the combination of the 1D barcode and the 2D barcode.
In a further aspect of the present invention, the 2D barcode selecting step comprises the step of selecting a method of combining the 1D barcode and the 2D barcode based on the reflectance.
In a further aspect of the present invention, the method comprises the step of selecting a spacing of marks in the 2D barcode to vary the reflectance relative to the threshold.
In a further aspect of the present invention, the method comprises the step of selecting a size of marks in the 2D barcode to vary the reflectivity relative to the threshold.
In a further aspect of the present invention, the method comprises the step of selecting a non-white, non-black color to print the 2D barcode in order to vary the reflectivity relative to the threshold.
In a yet further aspect of the present invention, the method comprises the step of selecting a level of gray to print the 2D barcode in order to vary the reflectivity relative to a threshold.
In a further aspect of the present invention, the printing step includes the step of selecting a ratio of dark marks to light marks to control reflectance of the printed 2D barcode combined with the 1D barcode.
In a further aspect of the present invention, the combining step comprises the step of selecting a method of combining based on a worst case reflectance approximation of at least one of a bar of the 1D barcode after the 2D barcode is combined with at least a portion of the 1D barcode bar, and a space of the 1D barcode after the 2D barcode is combined with at least a portion of the 1D barcode space, relative to a threshold reflectance.
In another embodiment, the invention comprises the steps of selecting a 1D barcode for a medium; selecting a multi-dimensional barcode for printing on the medium based on a threshold print contrast, PCS, after the 1D barcode and the multi-dimensional barcode are put together, wherein
PCS=(Rwxe2x88x92Rb)/Rwxc3x97100%,
where
Rw=minimum reflectivity of a space of the 1D barcode, with the multi-dimensional barcode put together therewith,
Rb=maximum reflectivity of a bar of the 1D barcode with the multi-dimensional barcode put together therewith.
In a yet further embodiment of the present invention, a printing system is provided for printing a 1D barcode and a multi-dimensional barcode in the same area comprising: a printing device; logic for obtaining a 1D bar code and a multi-dimensional barcode to be combined with the 1D bar code; logic for combining the 1D and 2D bar codes to overlap at least in part in an area; and logic for printing with the printing device the user selected multi-dimensional barcode and a 1D barcode in a same area of a medium.